OBSERVE: guidelines for the refinement of rodent cancer models

The Oncology Best-practices: Signs, Endpoints and Refinements for in Vivo Experiments (OBSERVE) guidelines are the result of a European initiative supported by EurOPDX and INFRAFRONTIER, and aim to facilitate the refinement of studies using in vivo cancer models by offering robust and practical recommendations on approaches to research scientists and animal care staff.

OBSERVE lists cancer-specific clinical signs as a reference point and from there developed sets of guidelines for a wide variety of rodent models, including genetically engineered models and patient derived xenografts. In this Consensus Statement, the authors systematically and comprehensively address refinement and monitoring approaches during the design and execution of murine cancer studies. They elaborate on the appropriate preparation of tumour-initiating biologicals and the refinement of tumour-implantation methods. 

The clinical signs to monitor tumour growth are discussed, along with the appropriate follow-up of animals tailored to varying clinical signs and humane endpoints, and an overview of severity assessment in relation to clinical signs, implantation method and tumour characteristics.